diff --git a/docs/contracts/u5_booth_manifest.contract.md b/docs/contracts/u5_booth_manifest.contract.md
index ca4bb3d..54e18cd 100644
--- a/docs/contracts/u5_booth_manifest.contract.md
+++ b/docs/contracts/u5_booth_manifest.contract.md
@@ -243,6 +243,13 @@ Deliberately deferred or never. Divergence here is not drift.
   manifest is a dotfile and every existing listing already skips it.
 - **Auth, or treating a manifest as trusted.** Standing non-goal; the Booth is
   LAN-internal and a hand-written `.booth.json` is a supported input.
+- **Provenance ON a verbatim-`index.html` booth's own page.** Five live booths
+  serve the author's HTML raw, and the Booth owns no header there to put a line
+  into — it currently reaches those pages through six regexes injected into
+  arbitrary markup, which is precisely the defect U3 exists to fix. Their INDEX
+  cards carry provenance like everything else; the page itself waits for U3's
+  declared embed seam. Verified on `pewpew-ui-brief`: page renders 200, card
+  reads `unannounced`.
 
 ## Invariants